Decatur, Ga. — "Yes, I am angry," principal Laurent Ditmann thumped the table. "This is now officially a damage-control situation."On a blazing August afternoon, Dr. Ditmann sat in the International Community School (ICS) office, gulping bottled water. His close-buzzed head glistened with sweat. He'd just answered the phone to a warning.The 7-year-old elementary school is up for charter renewal and is accountable for its successes, weaknesses, and future plans, and DeKalb County wanted changes. One was major: By the end of this school year, to fit Georgia's interpretation of No Child Left Behind, the school for refugee and American-born kids needed to show proof of state certification for teachers and credentials for assistant teachers. Without drastic action, three-quarters of its educators, including most former refugees, would become ineligible.Ditmann, the new replacement for ICS founding principal Bill Moon, was desperate: "This could be the thing that kills the school."Today, the educational experiment that's made Congolese refugee Bill Clinton Hadam at home in English-speaking America faces an uncertain future. As ICS's first kindergartners begin sixth grade, the school's survival depends on whether its new leader can solidify the founders' bold, messy, improbable vision into something lasting. Embodying the challenge in faith and practice are the two men who have led the school: Mr. Moon and Dr. Ditmann."Bill was the dreamer," says fifth-grade teacher Claire Hamilton, who's been with ICS since it opened. "Laurent is more of the doer. And I think the school's at a point now where we need a doer."The doer

"The most important thing in my life," says Ditmann, "happened 20 years before I was born." When the Nazis invaded France, his Jewish grandparents took their families into hiding in the countryside. One grandfather died in Auschwitz. The rest survived, and returned to Paris in 1944 as refugees.

At 12, their sober, curious grandson started visiting Les Invalides, the French military museum and retirement home, talking with elderly veterans. To the puzzlement of his father, who spent a lifetime trying to forget the trauma of war, Ditmann fixated on it.At 24, he left France to study in the US, where he married and got his PhD in French studies, focused on military history. By 35, Ditmann was tenured chair of foreign languages at Atlanta's Spelman College. Former students and colleagues remember him as a brilliant teacher. But after three years, disillusioned by institutional politics, he quit academia. For the next five years, he cast about - working at Tiffany & Co., selling pocket watches, consulting for businesses - wondering if his life had been a waste. Two years ago, he joined ICS as Moon's assistant and answered that question.

"He's very lucky," says Ditmann's wife, Mary. "He may be doing stuff for the school, but the school's doing a lot more for him, if truth be told."

The dreamer "I always doubted he loved me," Bill Moon says of his father, a California businessman who had little time for his shy, stuttering son. When his sister was born with cerebral palsy, Moon's parents fell apart - and at 16, he left the chaos of home for refuge in a Franciscan seminary. There, in Moon's senior year of high school, a teacher asked him to lead a class on John Donne.

When he stood before the roomful of boys and began, "Look at line three ... " he spoke without a stutter for the first time. "I was a teacher," he says. "I knew 10 seconds after I got up there. And this changed my life."

The novitiate wasn't for him; after college, he married and moved to Europe. For 14 years, his family scraped by as Moon taught at, and led, an array of international schools. Early on, they stumbled on a religious community in France called Taiz, where they returned each summer. Its charismatic leader encouraged Moon's goal of starting a school. Six kids later, the family returned to the US, where Moon led schools in California, Texas, and Georgia. Shortly before Moon's father died, he told his son he was proud of him. In his 60s, Moon left a comfortable job at the prestigious Atlanta International School to found ICS in 2002.

"It was something I dreamed about doing for 20 years," he says. When the opportunity came, "I said: this is it. This is one of those moments you seize."

Loaves, fishes, chalkboard earasers

ICS was built by believers. The "discernment group" that started the school included Catholics, Methodists, Muslims, Lutherans, and Orthodox Serbs. They describe the process as a "spiritual journey," a series of miracles.

Moon was an inspiring leader. He visited students in their homes; hugged everyone in the halls; described and embodied his vision of community so compellingly that staff, volunteers, and donors pitched in. He became the grandfatherly protector of a school that was more like a family.

"I don't see him like boss," says Sanela Misimovic, a Bosnian refugee whom Moon hired early on. "I see him as someone who helped me grow up here in America."

These gifts were also Moon's weaknesses. A busy procrastinator with a tiny staff and an aversion to delivering bad news, he didn't prioritize staff accreditation - even though, he admits, "we knew that this bee was eventually going to sting us."

"Bill took a lot of risks, and that's what you need in a start-up," says science teacher Leslie Taylor.

But running it was another thing. When Ditmann took over in August, he found a mess of loose ends that alarmed him.

Moon was adept at raising - often just in time, from friends - the $470,000 ICS needs annually to scrape by. But he never collected or analyzed data on student achievement, the kind that county and state authorities - and major donors - want to see."I adore the guy, [but] Bill lives in denial," says Ditmann. To him, this was irresponsible and infuriating. When Ditmann took over, he asked Ms. Taylor to manage school data, enlisted a research firm to analyze ICS successes and failures, and upped its private annual fundraising goal to $620,000. [Editor's note: The original version misstated the type of fundraising.]

An agnostic Jew, he sees a danger in assuming that ICS is specially blessed. The school is a mitzvah, he says, in the sense of a good thing that exists without guarantees.

Ditmann is nobody's grandpa. Until he went to work at ICS, his wife didn't know he liked children. He arrived with a hurried manner, a taste for obscure puns, and a melodramatic streak that colleagues describe as "very French."

"Laurent, he just come to meeting: OK, No. 1, No. 2, No. 3, I don't have time,' " says Burmese teaching assistant Htwe Htwe. "Mr. Moon a very heart person; he love our family."But Ditmann's whimsy - colorful costumes that his wife makes for him for school events; the flying toy helicopter on his desk - charmed colleagues. And right away, he made savvy changes: transforming his office into a gathering place and the school's best room into a media center, asking Moon to stay to help with fundraising, and promoting a "core team" of advisers.

Some staff, founders, and parents worry that the family spirit of ICS will be lost. But all agree that change was inevitable. In the past year, Moon's health has deteriorated. His wife Mary, who mans the ICS front desk, says, a little wistfully, that Ditmann has brought the place new vitality: "His popularity is a little like I remember it used to be for Bill."

Last month, in a move colleagues say Moon would never have made, Ditmann sat down with all 24 of ICS's teaching assistants to break the news about the county's credential demands: "I know it's easy for me to say, but don't worry We're gonna take care of you."

Assistant Nazdar Amedi, from Kurdistan, bit her fingers. Ms. Htwe looked like she might cry. Ditmann told them he was lobbying for a phase-in period for staff to meet the new requirements. In October, the county school board would vote.

"I repeat, don't worry," he said, as worried looks bloomed on more faces. "I don't mind going to war on this one."

Around the room, escapees from the world's war zones looked less sure.Tomorrow: Who gets left behind if ICS is forced to get rid of its refugee staff?